EP3049637B1 - Rotary assembly for turbomachine - Google Patents

Rotary assembly for turbomachine Download PDF

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Publication number
EP3049637B1
EP3049637B1 EP14790197.9A EP14790197A EP3049637B1 EP 3049637 B1 EP3049637 B1 EP 3049637B1 EP 14790197 A EP14790197 A EP 14790197A EP 3049637 B1 EP3049637 B1 EP 3049637B1
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EP
European Patent Office
Prior art keywords
disc
internal
annular
sealing means
external
Prior art date
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Application number
EP14790197.9A
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German (de)
French (fr)
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EP3049637A1 (en
Inventor
Mathieu Louis Jean LEDUC
Pierre-Louis Alexandre CARLOS
Clément ROUSSILLE
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Safran Aircraft Engines SAS
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Safran Aircraft Engines SAS
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Publication of EP3049637A1 publication Critical patent/EP3049637A1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
    • F01D11/005—Sealing means between non relatively rotating elements
    • F01D11/006—Sealing the gap between rotor blades or blades and rotor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/30—Fixing blades to rotors; Blade roots ; Blade spacers
    • F01D5/3007—Fixing blades to rotors; Blade roots ; Blade spacers of axial insertion type
    • F01D5/3015—Fixing blades to rotors; Blade roots ; Blade spacers of axial insertion type with side plates
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/02—Blade-carrying members, e.g. rotors
    • F01D5/08—Heating, heat-insulating or cooling means
    • F01D5/085—Heating, heat-insulating or cooling means cooling fluid circulating inside the rotor
    • F01D5/087—Heating, heat-insulating or cooling means cooling fluid circulating inside the rotor in the radial passages of the rotor disc
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/12—Blades
    • F01D5/22—Blade-to-blade connections, e.g. for damping vibrations
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/30—Fixing blades to rotors; Blade roots ; Blade spacers
    • F01D5/3007—Fixing blades to rotors; Blade roots ; Blade spacers of axial insertion type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
    • F01D11/001—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between stator blade and rotor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2220/00—Application
    • F05D2220/30—Application in turbines
    • F05D2220/32—Application in turbines in gas turbines
    • F05D2220/323—Application in turbines in gas turbines for aircraft propulsion, e.g. jet engines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2300/00—Materials; Properties thereof
    • F05D2300/60—Properties or characteristics given to material by treatment or manufacturing
    • F05D2300/603—Composites; e.g. fibre-reinforced
    • F05D2300/6033—Ceramic matrix composites [CMC]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T50/00—Aeronautics or air transport
    • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft

Definitions

  • the invention relates to a rotary assembly for a turbomachine, such as in particular an airplane turbojet, as well as to a turbomachine comprising such an assembly.
  • Such an assembly which is found in particular in a turbine, comprises a disk, and blades extending radially from the disk and whose roots are engaged axially and retained radially in the cells of the outer periphery of the disk, said cells being arranged alternately with the teeth of the disc.
  • the blades also include internal platforms arranged circumferentially end to end so as to together define the internal boundary of the flow stream of hot gases circulating in the turbine.
  • the part of the blade located internally with respect to the vein, that is to say between the internal platform and the foot, is called a stilt. According to this arrangement, spaces are formed between two adjacent stilts, and form inter-stilt or inter-blade cavities. So-called cell bottom cavities are also formed by radial spaces located between the blade roots and the bottoms of the cells.
  • a metal annular ring formed of a radial annular wall comprising a single radial slot, or formed approximately of seven sectors arranged end to end, is arranged downstream of the inter-blade cavities.
  • the outer annular end of the rod is inserted into a groove extending on the internal faces of the platforms, and its internal annular end is held tight against the teeth of the disc and the blade roots by a downstream element such as a maze ring.
  • the ring offers the advantage of having virtually no gas flow gaps, once fitted, and therefore ensures a good seal.
  • the rod presses on the platforms by centrifugal effect with a relatively high force, which risks undermining the integrity of the platforms, or requires them to be undesirably oversized. .
  • the platforms also made of CMC are even less able to support the weight of the rotating rod, the density ratio between a metallic material and a CMC material being between three and four.
  • the expansion ratio in temperature increase being between two and three, the differential expansions in operation between the ring on one side, and the blades and the disc on the other side, risk either accentuating the stresses generated on the platforms, or to allow clearances to appear allowing the flow of gas from the seams at the radial ends of the rod.
  • EP1 607 579 discloses a rotary assembly for a turbomachine according to the preamble of claim 1.
  • the present invention provides a simple, efficient and economical solution to the problem of sealing the inter-blade cavities, while overcoming the drawbacks associated with the solutions of the prior art.
  • the platforms support in rotation a much lower load, because the sealing means are split radially into two parts, only the outer part being retained in rotation by the platforms.
  • the internal part may be retained in rotation for example by the disc or by another rotating turbine element such as a labyrinth ring.
  • the load supported by the platforms by centrifugal effect can be greatly reduced, which opens up more design freedom at the level of the blade, such as a CMC design, and more generally makes it possible to reduce the fatigue of the platforms.
  • the two parts of the sealing means are capable of relative radial displacements, the differential expansions only involve a modification of the relative radial position of the two parts, and do not lead to the creation of stresses or play between the means. sealing and platforms.
  • the radial ends facing the inner annular part and the outer annular part are capable of relative radial displacements by sliding in a sealed manner.
  • the sealing means of the invention are formed downstream of said annular zone in order to allow pressurization of the inter-blade cavities to a value substantially identical to that of the stream gases, which limits the effect of suction into these cavities.
  • the internal annular part and the external annular part of the sealing means respectively comprise two rings held axially and radially with respect to the annular zone extending radially between the platforms and the disc.
  • Such insert rings seal the inter-blade cavities in a particularly effective manner, since their assembly can easily be carried out without the formation of clearances letting the stream gases leak.
  • These rings can be split or sectorized rods, depending on the assembly needs.
  • air circulation means are formed on the disc and/or the internal part of the sealing means, and configured in such a way as to allow air to circulate between the upstream and/or the downstream of the rotating assembly and the cell bottoms.
  • a cooling air can circulate freely axially through the bottoms of the cells, in order to ensure the cooling of the disk.
  • the external part of the sealing means comprises an external end engaged in a radial annular groove formed on the internal faces of the platforms.
  • the internal part of the sealing means provides axial locking of the external part against the annular zone extending radially from the platforms to the disk.
  • the internal part of the sealing means is held radially by the disk.
  • the internal part of the sealing means can advantageously be held axially against the disk and the blades by an annular arm of a sealing ring comprising annular wipers intended to cooperate in a sealed manner with an external stator element.
  • An axial contact will advantageously be made between the internal part of the sealing means and the assembly consisting of the disc and the blades at least radially at the level of the bearing zones between the teeth of the disc and the blade roots in operation, this in order to ensure sealing between the cell bottom cavities and the inter-blade cavities.
  • the internal part of the sealing means comprises an annular hooked part engaged with at least one rim of one of the faces of the disc for relative radial blocking.
  • the rims of the disc are formed by internal faces of several projecting portions located on one of the faces of the disc internally with respect to the bottoms of the cells of the disc, and following each other circumferentially in a discontinuous manner.
  • the cooling air entering or leaving the cells can circulate radially between the annular hook of the internal part and the disc, as well as at the level of the discontinuities formed between the projecting portions, and can therefore communicate with an element foreign to the rotary assembly.
  • the internal part of the sealing means can easily provide sealing between the cell bottom cavities and the inter-blade cavities outside the annular hooked part.
  • the rims of the disc can in another way be formed by internal faces of several projecting portions located on the external parts of the radial faces of the teeth of the disc, and following each other circumferentially in a discontinuous manner, the internal end of the annular part hook engaged on these internal faces further being in axial contact with the teeth of the disc and the blade roots at the level of the bearing points of the teeth of the disc against the blade roots in operation.
  • the annular hooked part leaves free the circulation of air through the bottom cavities of the cells.
  • the seal between the cell bottom cavities and the inter-blade cavities is maintained by virtue of the inner end of the annular hook portion in contact with the teeth of the disk and the blade roots.
  • the outer part of the sealing means comprises a frustoconical wall extending inwards from its outer end
  • the inner part of the sealing means comprises at its outer end an annular recessed rim and bearing axially against the inner end of the frustoconical wall, which can slide radially along the recessed edge of the inner part.
  • An annular seal is interposed axially between the axial ends of the blades and the frustoconical wall of the outer part in order to press the inner end of the frustoconical wall in a leaktight manner against the annular flange offset from the inner part.
  • the annular seal in rotation, extends outwards and constrains the frustoconical wall against the recessed rim of the internal part, so as to ensure optimum sealing.
  • the internal part of the sealing means is connected at its external end to two radial annular branches spaced axially from each other, and the external part comprises a radial annular wall whose internal end is engaged between the two branches of the inner part and can move therein radially, the axial play separating the two branches with respect to the radial annular wall being substantially zero.
  • the pressure difference between the inter-blade cavities and the upstream and/or downstream parts of the rotating assembly in connection with the vein generates an angular offset between the branches of the part internal and the radial wall of the external part.
  • This angular offset induces a bearing along a circumferential line between at least one of the branches and the radial wall, which provides sealing.
  • the vanes are of ceramic matrix composite. As explained above, the invention allows the use of such a material at the level of the blades without risking damage to the platforms.
  • the invention also relates to a turbomachine turbine comprising a rotary assembly as described in the present patent application.
  • the invention finally relates to a turbomachine, such as a turbojet or a turboprop, comprising a rotary assembly as described in the present patent application.
  • FIG 1 which represents a low pressure turbine 10 according to the prior art, arranged downstream of a high pressure turbine 12, and at the figure 2 which more particularly represents two vanes 14 mounted on a rotating disc 16 of this turbine 10.
  • the low pressure turbine 10 comprises an axial alternation of stages of annular rows of fixed vanes 18, called distributors, and stages of rotating discs 16 comprising at their peripheries a plurality of vanes 14, these stages being arranged around an axis X of the turbomachine.
  • upstream AM and downstream AV are defined so that the upstream is axially on the side from which the general flow of the turbomachine originates, and the downstream is located axially on the side towards which this same flow flows.
  • Each disc 16 comprises at its outer periphery teeth (whose top is referenced 20) arranged alternately with cells (whose bottom is referenced 22) in which are axially engaged and radially retained blade roots (whose end internal is referenced 24), these blades 14 extending radially from the cells 22 in an annular flow path 26 of a flow of hot gas from an upstream combustion chamber (not shown).
  • each blade comprises radially from the outside inwards a blade 28, a platform 30 extending substantially perpendicularly with respect to the axis of elongation of the blade 14, and a stilt 32 connecting the platform at the blade root 24.
  • the blade roots 24 have a shape, for example dovetail or the like, to ensure their radial retention in the cells 22.
  • the platforms 30 of the blades are arranged circumferentially end to end. tip so as to define together the ideal internal limit of the flow rate of the hot gases circulating in the turbine. According to this arrangement, spaces are formed between two circumferentially adjacent stilts 32, in the annular zone extending radially from the platforms 30 to the disc 16, and are called inter-stilt or inter-blade cavities 34.
  • So-called cell bottom cavities 36 are also formed by radial spaces separating the blade roots 24 funds 22 of the cells.
  • Walls 38, 40 extend radially inwards from upstream and downstream of the platforms as far as the roots 24 of the blades and form axial sealing means for the annular zone extending radially from the platforms 30 up to disc 16, and therefore inter-blade cavities 34, ensuring their closure.
  • inter-blade cavities 34 This axial sealing of the inter-blade cavities 34 is important, because if part of the stream gas circulates through these cavities, it does not participate in the rotational drive of the blades 14 and directly heats the teeth 20 of the disc forming the bottom. inter-blade cavities 34, which leads to an increase in the temperature of the discs 16 which can damage them and reduce their service life.
  • the upstream radial wall 38 of the platform is connected to a spoiler 42 extending upstream and the radial downstream wall 40 is connected to a spoiler 44 extending downstream.
  • the spoilers 42, 44 extend axially between consecutive stages of the turbine in order to partially preserve the structural integrity of the stream 26 between each stage of the turbine, which limits the circulation of hot gases radially inward of the turbine.
  • the discs are fixed to each other by bolting, at 46, annular flanges 48, 50 extending axially towards each other from each disc.
  • a labyrinth ring 52 is also positioned axially between each pair of adjacent discs 16 and comprises upstream and downstream annular arms 54, 56 extending axially as far as these discs. The fixing flanges 48, 50 between the discs are thus protected from the stream gases by the arms 54, 56 of the labyrinth ring 52.
  • the labyrinth ring 52 also comprises an internal radial annular wall 58 for fixing to the bolting 46 of the flanges 48, 50 of the discs, and cooperates via external annular wipers 60 with the ends inside the vanes 18 of the distributors, in order to limit the flow of stream gases internally with respect to these vanes 18.
  • cooling air A is taken, from a low-pressure or high-pressure compressor for example, and routed to the internal part of the turbine as far as the cell bottom cavities. 36 in order to ensure the cooling of the disk 16 and to protect the latter from the heating caused by the hot gases of the stream flow 26.
  • the latter open downstream internally with respect to the arm 54 of the labyrinth ring 52 in axial support on the disc 16. This configuration allows the cooling air A to circulate further downstream radially between the labyrinth ring 52 and the flanges 48, 50 for fixing between the discs 16, in order to also ensure the cooling thereof.
  • the hot gases circulating in the stream 26 can circulate through the interstices 62 formed between the circumferential facing edges of the upstream and downstream radial walls 38, 40 connected to the platforms 30 and axially covering the internal cavities. -blades 34.
  • the number of interstices 62 is relatively high since it directly depends on the number of platforms 30 forming the internal limit of the stream, which induces a non-negligible total leak through the inter-blade cavities, which impairs turbine performance.
  • the geometry of the assembly formed by these radial walls 38, 40 and the platforms 30 does not allow the blades to be made of Ceramic Matrix Composite (C.M.C.), because this would in particular generate problems of fiber bending. material during manufacture. Recent developments lead to the use of blades made of C.M.C. The use of this type of material makes it possible to reduce the weight of the blades and to increase their resistance to high temperatures.
  • sealing means which can be arranged upstream and/or more advantageously downstream of this zone, and being presented in two annular parts structurally distinct from each other, one internal 64 and the other external 66.
  • only the external part 66 of the sealing means is retained by the platforms 30 in rotation.
  • the load supported by the platforms 30 is reduced.
  • their radial ends are also formed so as to slide one over the other in a sealed manner.
  • the solution proposed, according to the main characteristics mentioned above, can be broken down structurally according to three non-limiting examples represented the first in figures 3 and 4 , the second to figure 5 , and the third to the figure 6 .
  • the sealing means are formed downstream of the annular zone extending radially from the platforms 30 to the disk 16, and comprising the inter-blade cavities 34. Equivalently and symmetrically, it is possible to place these sealing means upstream of this zone.
  • the platforms 30 are connected at their upstream ends to walls 38 extending radially as far as the teeth 20 of the discs, and each comprising in the vicinity of their internal ends spoilers 42 extending towards upstream.
  • the platforms 30 are also each connected at their downstream ends to a spoiler 44 extending downstream.
  • the internal part 64 of the sealing means is formed of a ring, that is to say of a piece extending annularly, preferably split, but which can also be formed of several sectors arranged circumferentially end to end. .
  • This internal ring 64 extends radially from the inside outwards from a zone of the disc located between the cells 22 and the flanges 48 of the disc 16 up to approximately the middle of the stilts 32. It comprises a main radial wall 67 which is held against the downstream ends of the stilts 32 and the teeth 20 of the disc by an upstream annular arm 54 of a downstream labyrinth ring.
  • the inner ring 64 further comprises at its inner end an annular hook part 68 engaged on the disk 16, and intended to block the ring 64 radially.
  • This hook part 68 connected to the inner end of the radial wall main 67, begins to extend radially from the outside outward at the level of the teeth 20 of the disc, just inside the bearing zone of the annular arm 54 of the labyrinth ring, and at the inside the bearing areas between the teeth 20 of the disc and the blade roots 24 in operation. It comprises an annular wall 70 spaced axially from the disc 16 and extending inwards, and connected at its inner end to an annular rim 72 facing upstream.
  • This flange 72 engages with projecting portions 74 formed discontinuously circumferentially on the downstream face of the disc 16, radially between the teeth 20 of the disc and the flanges 48, and which each comprise an internal cylindrical wall supporting the flange. 72 of the crochet part 68.
  • the cooling air A coming from the cell bottom cavities can escape downstream in the axial annular space left between the disc 16 and the hook part 68, and circulate inwards between the projecting portions 74 of the disc, between the flange 72 of the hooked part and the disc, to finally follow axially the downstream flange 48 of the disc.
  • the internal part 64 of the sealing means comprises at its external end an annular flange 76 offset downstream with respect to the main radial wall 67. This flange is intended to come into axial abutment upstream against the external part 66 sealing means to ensure the axial retention against the blades 14.
  • the outer part 66 of the sealing means is formed of a ring, that is to say of a part extending annularly, preferably formed of six to eight sectors arranged circumferentially end to end, but which can also be split.
  • This outer ring 66 extends radially from the platforms 30 to the recessed outer edge 76 of the inner part of the sealing means. It comprises a main frustoconical wall 78 extending inwards and downstream from an outer end engaged in a radial groove 80 formed on the internal faces of the platforms 30.
  • the frustoconical wall 78 is further connected to its inner end to an annular rim 82 facing upstream.
  • An annular seal 84 is arranged axially between the downstream ends of the stilts 32, and the internal part of the frustoconical wall 78.
  • the seal 84 is retained radially by the internal rim 82 of the frustoconical wall.
  • the internal end of the frustoconical wall 78 is arranged in contact on the upstream face of the external rim 76 offset from the internal part 64 of the sealing means.
  • the annular seal 84 extends circumferentially and pushes the frustoconical wall 78 downstream, which makes it possible to axially constrain the internal end of the frustoconical wall 78 against the recessed rim 76 of the internal part, so as to to seal the interface between the internal part 64 and the external part 66 of the sealing means.
  • the recessed edge 76 of the internal part has a sufficient radial dimension to allow the internal end of the frustoconical wall 78 to slide radially along its upstream surface, while maintaining the seal between the two parts.
  • the construction differs from the example shown in figures 3 and 4 only in that the radial wall 67 of the internal part 64 of the sealing means is connected at its external end to two radial branches 86, 88 spaced apart axially, similarly to a fork, and in that the external part 66 sealing means comprises an annular radial wall 90 extending from its outer end, and engaging axially between the two radial branches 86, 88.
  • the pressure difference between the inter-blade cavities 34 and the zone downstream of the sealing means induces a downstream rotation of the ends facing the internal 64 and external 66 parts of the sealing means. , which brings the radial wall 90 of the outer part into contact against one of the branches 86, 88 of the inner part, in order to ensure sealing.
  • a sliding between the two parts is authorized by the radial dimension of the branches, while retaining the seal.
  • the construction differs from the example shown in figures 3 and 4 only in that the projecting portions 74' are formed not radially between the cells 22 and the flanges 48, but on the teeth 20 of the disc, externally to the cell bottom cavities 36.
  • the main wall 67' of the part 64' of the sealing means is shortened radially so that the annular hook part 68' engages via its internal edge 72' on these projecting portions 74'.
  • the annular arm 54 of the downstream labyrinth ring no longer rests on the main wall 67, but on the annular wall 70' of the hook part 68'.
  • this solution makes it possible to reduce the stresses exerted on the internal part of the sealing means, since its smaller size makes it possible to avoid the appearance of significant thermal gradients.
  • the location of the protruding portions 74' on the teeth 20 of the disc implies a concentration of higher mechanical stresses at the level of the internal parts of the teeth 20 of the disc attached to the disc, these protruding portions 74' serving to retain the the internal part of the sealing means in operation.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)

Description

L'invention se rapporte à un ensemble rotatif pour turbomachine, telle qu'en particulier un turboréacteur d'avion, ainsi qu'à une turbomachine comprenant un tel ensemble.The invention relates to a rotary assembly for a turbomachine, such as in particular an airplane turbojet, as well as to a turbomachine comprising such an assembly.

Un tel ensemble, que l'on retrouve notamment dans une turbine, comprend un disque, et des aubes s'étendant radialement depuis le disque et dont les pieds sont engagés axialement et retenus radialement dans des alvéoles de la périphérie externe du disque, lesdites alvéoles étant disposées en alternance avec des dents du disque. Les aubes comprennent également des plates-formes internes agencées circonférentiellement bout à bout de manière à définir ensemble la limite interne du flux d'écoulement des gaz chauds circulant dans la turbine. La partie de l'aube située intérieurement par rapport à la veine, c'est-à-dire entre la plate-forme interne et le pied, est appelée échasse. Selon cette disposition, des espaces sont formés entre deux échasses adjacentes, et forment des cavités inter-échasses ou inter-aubes. Des cavités dites de fond d'alvéole sont également formées par des espaces radiaux situés entre les pieds d'aubes et les fonds des alvéoles.Such an assembly, which is found in particular in a turbine, comprises a disk, and blades extending radially from the disk and whose roots are engaged axially and retained radially in the cells of the outer periphery of the disk, said cells being arranged alternately with the teeth of the disc. The blades also include internal platforms arranged circumferentially end to end so as to together define the internal boundary of the flow stream of hot gases circulating in the turbine. The part of the blade located internally with respect to the vein, that is to say between the internal platform and the foot, is called a stilt. According to this arrangement, spaces are formed between two adjacent stilts, and form inter-stilt or inter-blade cavities. So-called cell bottom cavities are also formed by radial spaces located between the blade roots and the bottoms of the cells.

Afin d'améliorer les performances de la turbomachine, et d'éviter l'échauffement du disque par le flux des gaz chauds issus d'une chambre de combustion amont et s'écoulant à travers la veine, il est important de limiter au maximum la circulation de ces gaz sous les plates-formes et à travers les cavités inter-aubes, à l'aide de moyens d'étanchéité. En effet, la partie des gaz de veine s'écoulant sous les plates-formes ne participe pas à l'entrainement en rotation des aubes et chauffe directement les dents du disque. Il est particulièrement avantageux d'agencer les moyens d'étanchéité à l'aval des cavités inter-aubes afin d'autoriser une pressurisation de ces cavités à une valeur sensiblement identique à celle des gaz de veine, ce qui limite l'effet d'aspiration dans les cavités.In order to improve the performance of the turbomachine, and to avoid heating of the disc by the flow of hot gases from an upstream combustion chamber and flowing through the stream, it is important to limit the circulation of these gases under the platforms and through the inter-blade cavities, using sealing means. In fact, the part of the stream gases flowing under the platforms does not take part in driving the blades in rotation and directly heats the teeth of the disc. It is particularly advantageous to arrange the sealing means downstream of the inter-blade cavities in order to allow pressurization of these cavities to a value substantially identical to that of the stream gases, which limits the effect of suction in the cavities.

A cette fin, il est connu de prolonger les plates-formes à leurs extrémités amont et/ou aval par des parois s'étendant radialement vers l'intérieur jusqu'aux dents du disque afin d'obturer axialement les cavités inter-aubes. Toutefois, chaque couple de parois adjacentes est inévitablement séparé circonférentiellement par un interstice autorisant la circulation des gaz de veine. Le nombre d'interstices, correspondant au nombre d'aubes, est alors trop important pour permettre une étanchéité acceptable des cavités inter-aubes.To this end, it is known to extend the platforms to their upstream and/or downstream ends by walls extending radially inwards as far as the teeth of the disc in order to axially close the inter-blade cavities. However, each pair of adjacent walls is inevitably separated circumferentially by a gap allowing the flow of stream gases. The number of interstices, corresponding to the number of blades, is then too great to allow acceptable sealing of the inter-blade cavities.

Selon une autre solution connue, un jonc annulaire métallique, formé d'une paroi annulaire radiale comprenant une seule fente radiale, ou formée approximativement de sept secteurs agencés bout à bout, est agencé en aval des cavités inter-aubes. L'extrémité annulaire externe du jonc est insérée dans une gorge s'étendant sur les faces internes des plates-formes, et son extrémité annulaire interne est maintenue serrée contre les dents du disque et les pieds d'aubes par un élément aval tel qu'un anneau labyrinthe. Le jonc offre l'avantage de ne présenter quasiment aucun interstice de circulation des gaz, une fois monté, et assure donc une bonne étanchéité. Toutefois, en rotation, le jonc s'appuie sur les plates-formes par effet centrifuge avec un effort relativement important, ce qui risque de porter atteinte à l'intégrité des plates-formes, ou nécessite de sur-dimensionner de manière indésirable ces dernières.According to another known solution, a metal annular ring, formed of a radial annular wall comprising a single radial slot, or formed approximately of seven sectors arranged end to end, is arranged downstream of the inter-blade cavities. The outer annular end of the rod is inserted into a groove extending on the internal faces of the platforms, and its internal annular end is held tight against the teeth of the disc and the blade roots by a downstream element such as a maze ring. The ring offers the advantage of having virtually no gas flow gaps, once fitted, and therefore ensures a good seal. However, in rotation, the rod presses on the platforms by centrifugal effect with a relatively high force, which risks undermining the integrity of the platforms, or requires them to be undesirably oversized. .

En outre, lorsque les aubes sont réalisées en Composite à Matrice Céramique (dans la suite abrégé en C.M.C.), les plates-formes également en C.M.C. sont encore moins aptes à supporter le poids du jonc en rotation, le rapport de densité entre un matériau métallique et un matériau C.M.C. étant compris entre trois et quatre. De plus, le rapport de dilatation en augmentation de température étant compris entre deux et trois, les dilatations différentielles en fonctionnement entre le jonc d'un côté, et les aubes et le disque d'un autre côté, risquent soit d'accentuer les contraintes engendrées sur les plates-formes, soit de laisser apparaitre des jeux autorisant la circulation des gaz de veines au niveau des extrémités radiales du jonc.In addition, when the blades are made of Ceramic Matrix Composite (hereinafter abbreviated to CMC), the platforms also made of CMC are even less able to support the weight of the rotating rod, the density ratio between a metallic material and a CMC material being between three and four. In addition, the expansion ratio in temperature increase being between two and three, the differential expansions in operation between the ring on one side, and the blades and the disc on the other side, risk either accentuating the stresses generated on the platforms, or to allow clearances to appear allowing the flow of gas from the seams at the radial ends of the rod.

EP1 607 579 divulgue un ensemble rotatif pour turbomachine selon le préambule de la revendication 1. EP1 607 579 discloses a rotary assembly for a turbomachine according to the preamble of claim 1.

La présente invention apporte une solution simple, efficace et économique au problème d'étanchéité des cavités inter-aubes, tout en s'affranchissant des inconvénients liés aux solutions de l'art antérieur.The present invention provides a simple, efficient and economical solution to the problem of sealing the inter-blade cavities, while overcoming the drawbacks associated with the solutions of the prior art.

A cette fin, elle propose un ensemble rotatif pour turbomachine, selon la revendication 1.To this end, it proposes a rotary assembly for a turbomachine, according to claim 1.

Grâce à l'invention, les plates-formes supportent en rotation une charge bien moins importante, car les moyens d'étanchéité sont dissociés radialement en deux parties, seule la partie externe étant retenue en rotation par les plates-formes. La partie interne pourra être retenue en rotation par exemple par le disque ou par un autre élément rotatif de turbine tel qu'un anneau labyrinthe. Ainsi, la charge supportée par les plates-formes par effet centrifuge peut être très fortement réduite ce qui ouvre plus de liberté de conception au niveau de l'aube, telle qu'une conception en C.M.C., et permet plus généralement de diminuer la fatigue des plates-formes. Par ailleurs, comme les deux parties des moyens d'étanchéité sont capables de déplacements radiaux relatifs, les dilatations différentielles impliquent seulement une modification de la position radiale relative des deux parties, et n'entrainent pas la création de contraintes ou du jeu entre les moyens d'étanchéité et les plates-formes. Enfin, le glissement entre les extrémités radiales en vis-à-vis des deux parties permet de conserver une étanchéité axiale de la zone annulaire s'étendant radialement depuis les plates-formes jusqu'au disque, qui comprend les cavités inter-aubes, cette étanchéité étant équivalente à celle permise par des moyens d'étanchéité formés d'un seul élément annulaire.Thanks to the invention, the platforms support in rotation a much lower load, because the sealing means are split radially into two parts, only the outer part being retained in rotation by the platforms. The internal part may be retained in rotation for example by the disc or by another rotating turbine element such as a labyrinth ring. Thus, the load supported by the platforms by centrifugal effect can be greatly reduced, which opens up more design freedom at the level of the blade, such as a CMC design, and more generally makes it possible to reduce the fatigue of the platforms. Furthermore, as the two parts of the sealing means are capable of relative radial displacements, the differential expansions only involve a modification of the relative radial position of the two parts, and do not lead to the creation of stresses or play between the means. sealing and platforms. Finally, the sliding between the radial ends facing the two parts makes it possible to maintain axial sealing of the annular zone extending radially from the platforms to the disc, which includes the inter-blade cavities, this sealing being equivalent to that permitted by sealing means formed of a single annular element.

En particulier, les extrémités radiales en vis-à-vis de la partie annulaire interne et de la partie annulaire externe sont capables de déplacements radiaux relatifs par glissement de façon étanche.In particular, the radial ends facing the inner annular part and the outer annular part are capable of relative radial displacements by sliding in a sealed manner.

En particulier, du fait des déplacements radiaux possibles entre lesdites parties annulaires externes et internes, seule une reprise des efforts centrifuges de la partie externe est assurée en rotation par les plates-formes.In particular, because of the possible radial displacements between said external and internal annular parts, only a take-up of the centrifugal forces of the external part is ensured in rotation by the platforms.

Préférentiellement, les moyens d'étanchéité de l'invention sont formés en aval de ladite zone annulaire afin d'autoriser une pressurisation des cavités inter-aubes à une valeur sensiblement identique à celle des gaz de veine, ce qui limite l'effet d'aspiration dans ces cavités.Preferably, the sealing means of the invention are formed downstream of said annular zone in order to allow pressurization of the inter-blade cavities to a value substantially identical to that of the stream gases, which limits the effect of suction into these cavities.

Selon une autre caractéristique de l'invention, la partie annulaire interne et la partie annulaire externe des moyens d'étanchéité comprennent respectivement deux anneaux maintenus axialement et radialement au regard de la zone annulaire s'étendant radialement entre les plates-formes et le disque.According to another characteristic of the invention, the internal annular part and the external annular part of the sealing means respectively comprise two rings held axially and radially with respect to the annular zone extending radially between the platforms and the disc.

De tels anneaux rapportés étanchéifient de manière particulièrement efficace les cavités inter-aubes, car leur montage peut facilement être effectué sans formation de jeux laissant fuir les gaz de veine.Such insert rings seal the inter-blade cavities in a particularly effective manner, since their assembly can easily be carried out without the formation of clearances letting the stream gases leak.

Ces anneaux peuvent être des joncs fendus ou sectorisés, en fonction des besoins de montage.These rings can be split or sectorized rods, depending on the assembly needs.

Préférentiellement, des moyens de circulation d'air sont formés sur le disque et/ou la partie interne des moyens d'étanchéité, et configurés de manière à autoriser de l'air à circuler entre l'amont et/ou l'aval de l'ensemble rotatif et les fonds d'alvéoles.Preferably, air circulation means are formed on the disc and/or the internal part of the sealing means, and configured in such a way as to allow air to circulate between the upstream and/or the downstream of the rotating assembly and the cell bottoms.

En effet, il est important que malgré le montage des moyens d'étanchéité selon l'invention, un air de refroidissement puisse circuler librement axialement à travers les fonds des alvéoles, afin d'assurer le refroidissement du disque.Indeed, it is important that despite the mounting of the sealing means according to the invention, a cooling air can circulate freely axially through the bottoms of the cells, in order to ensure the cooling of the disk.

Selon une autre caractéristique de l'invention, la partie externe des moyens d'étanchéité comprend une extrémité externe engagée dans une gorge annulaire radiale formée sur les faces internes des plates-formes. De préférence, la partie interne des moyens d'étanchéité assure un blocage axial de la partie externe contre la zone annulaire s'étendant radialement depuis les plates-formes jusqu'au disque.According to another characteristic of the invention, the external part of the sealing means comprises an external end engaged in a radial annular groove formed on the internal faces of the platforms. Preferably, the internal part of the sealing means provides axial locking of the external part against the annular zone extending radially from the platforms to the disk.

Avantageusement, la partie interne des moyens d'étanchéité est maintenue radialement par le disque.Advantageously, the internal part of the sealing means is held radially by the disk.

La partie interne des moyens d'étanchéité peut être avantageusement maintenue axialement contre le disque et les aubes par un bras annulaire d'un anneau d'étanchéité comprenant des léchettes annulaires destinées à coopérer de façon étanche avec un élément de stator externe.The internal part of the sealing means can advantageously be held axially against the disk and the blades by an annular arm of a sealing ring comprising annular wipers intended to cooperate in a sealed manner with an external stator element.

Un contact axial sera avantageusement réalisé entre la partie interne des moyens d'étanchéité et l'ensemble constitué du disque et des aubes au moins radialement au niveau des zones d'appui entre les dents du disque et les pieds d'aubes en fonctionnement, ceci afin d'assurer l'étanchéité entre les cavités de fond d'alvéole et les cavités inter-aube.An axial contact will advantageously be made between the internal part of the sealing means and the assembly consisting of the disc and the blades at least radially at the level of the bearing zones between the teeth of the disc and the blade roots in operation, this in order to ensure sealing between the cell bottom cavities and the inter-blade cavities.

Préférentiellement, la partie interne des moyens d'étanchéité comprend une partie annulaire en crochet engagée avec au moins un rebord d'une des faces du disque pour un blocage relatif radial.Preferably, the internal part of the sealing means comprises an annular hooked part engaged with at least one rim of one of the faces of the disc for relative radial blocking.

Dans une réalisation particulière de l'invention, les rebords du disque sont formés par des faces internes de plusieurs portions en saillie situées sur une des faces du disque intérieurement par rapport aux fonds des alvéoles du disque, et se suivant circonférentiellement de manière discontinue.In a particular embodiment of the invention, the rims of the disc are formed by internal faces of several projecting portions located on one of the faces of the disc internally with respect to the bottoms of the cells of the disc, and following each other circumferentially in a discontinuous manner.

Avantageusement, la partie annulaire en crochet de la partie interne des moyens d'étanchéité s'étend radialement depuis la zone située radialement entre :

  • les points d'appui des dents du disque contre les pieds d'aubes en fonctionnement, et
  • les fonds des alvéoles,
jusqu'aux faces internes des portions en saillie, et n'est en outre pas en appui axial contre le disque au moins localement.Advantageously, the annular hook part of the internal part of the sealing means extends radially from the zone located radially between:
  • the bearing points of the teeth of the disk against the blade roots in operation, and
  • cell bottoms,
up to the internal faces of the projecting portions, and furthermore is not in axial abutment against the disk, at least locally.

Grâce à cette réalisation, l'air de refroidissement en entrée ou en sortie des alvéoles peut circuler radialement entre le crochet annulaire de la partie interne et le disque, ainsi qu'au niveau des discontinuités formées entre les portions en saillie, et peut donc communiquer avec un élément étranger à l'ensemble rotatif. De plus, la partie interne des moyens d'étanchéité peut facilement assurer l'étanchéité entre les cavités de fond d'alvéole et les cavités inter-aubes à l'extérieur de la partie annulaire en crochet.Thanks to this embodiment, the cooling air entering or leaving the cells can circulate radially between the annular hook of the internal part and the disc, as well as at the level of the discontinuities formed between the projecting portions, and can therefore communicate with an element foreign to the rotary assembly. In addition, the internal part of the sealing means can easily provide sealing between the cell bottom cavities and the inter-blade cavities outside the annular hooked part.

Les rebords du disque peuvent d'une autre manière être formés par des faces internes de plusieurs portions en saillie situées sur les parties externes des faces radiales des dents du disque, et se suivant circonférentiellement de manière discontinue, l'extrémité interne de la partie annulaire en crochet engagée sur ces faces internes étant en outre en contact axial avec les dents du disque et les pieds d'aubes au niveau des points d'appui des dents du disque contre les pieds d'aubes en fonctionnement.The rims of the disc can in another way be formed by internal faces of several projecting portions located on the external parts of the radial faces of the teeth of the disc, and following each other circumferentially in a discontinuous manner, the internal end of the annular part hook engaged on these internal faces further being in axial contact with the teeth of the disc and the blade roots at the level of the bearing points of the teeth of the disc against the blade roots in operation.

Grâce à cette réalisation, la partie annulaire en crochet laisse libre la circulation de l'air à travers les cavités de fond d'alvéoles. De plus, l'étanchéité entre les cavités de fond d'alvéole et les cavités inter-aubes est conservée grâce à l'extrémité interne de la partie annulaire en crochet en contact sur les dents du disque et les pieds d'aubes.Thanks to this embodiment, the annular hooked part leaves free the circulation of air through the bottom cavities of the cells. In addition, the seal between the cell bottom cavities and the inter-blade cavities is maintained by virtue of the inner end of the annular hook portion in contact with the teeth of the disk and the blade roots.

Selon un premier mode de réalisation, la partie externe des moyens d'étanchéité comprend une paroi tronconique s'étendant vers l'intérieur depuis son extrémité externe, et la partie interne des moyens d'étanchéité comprend à son extrémité externe un rebord annulaire en décrochement et en appui axial contre l'extrémité interne de la paroi tronconique, laquelle peut glisser radialement le long du rebord en décrochement de la partie interne. Un joint annulaire est intercalé axialement entre les extrémités axiales des aubes et la paroi tronconique de la partie externe afin d'appuyer de façon étanche l'extrémité interne de la paroi tronconique contre le rebord annulaire en décrochement de la partie interne.According to a first embodiment, the outer part of the sealing means comprises a frustoconical wall extending inwards from its outer end, and the inner part of the sealing means comprises at its outer end an annular recessed rim and bearing axially against the inner end of the frustoconical wall, which can slide radially along the recessed edge of the inner part. An annular seal is interposed axially between the axial ends of the blades and the frustoconical wall of the outer part in order to press the inner end of the frustoconical wall in a leaktight manner against the annular flange offset from the inner part.

Grâce à ce mode de réalisation, en rotation, le joint annulaire s'étend vers l'extérieur et contraint la paroi tronconique contre le rebord en décrochement de la partie interne, de façon à assurer une étanchéité optimale.Thanks to this embodiment, in rotation, the annular seal extends outwards and constrains the frustoconical wall against the recessed rim of the internal part, so as to ensure optimum sealing.

Selon un second mode de réalisation, la partie interne des moyens d'étanchéité est reliée à son extrémité externe à deux branches annulaires radiales espacées axialement l'une de l'autre, et la partie externe comprend une paroi annulaire radiale dont l'extrémité interne est engagée entre les deux branches de la partie interne et peut s'y déplacer radialement, le jeu axial séparant les deux branches par rapport à la paroi annulaire radiale étant sensiblement nul.According to a second embodiment, the internal part of the sealing means is connected at its external end to two radial annular branches spaced axially from each other, and the external part comprises a radial annular wall whose internal end is engaged between the two branches of the inner part and can move therein radially, the axial play separating the two branches with respect to the radial annular wall being substantially zero.

En fonctionnement, la différence de pression entre les cavités inter-aubes et les parties amont et/ou aval de l'ensemble rotatif en liaison avec la veine engendre un décalage angulaire entre les branches de la partie interne et la paroi radiale de la partie externe. Ce décalage angulaire induit un appui le long d'une ligne circonférentielle entre au moins l'une des branches et la paroi radiale, ce qui assure l'étanchéité.In operation, the pressure difference between the inter-blade cavities and the upstream and/or downstream parts of the rotating assembly in connection with the vein generates an angular offset between the branches of the part internal and the radial wall of the external part. This angular offset induces a bearing along a circumferential line between at least one of the branches and the radial wall, which provides sealing.

Dans un mode de réalisation préféré de l'invention, les aubes sont à composite à matrice céramique. Comme expliqué plus haut, l'invention permet l'utilisation d'un tel matériau au niveau des aubes sans risquer l'endommagement des plates-formes.In a preferred embodiment of the invention, the vanes are of ceramic matrix composite. As explained above, the invention allows the use of such a material at the level of the blades without risking damage to the platforms.

L'invention concerne également une turbine de turbomachine comprenant un ensemble rotatif tel que décrit dans la présente demande de brevet.The invention also relates to a turbomachine turbine comprising a rotary assembly as described in the present patent application.

L'invention concerne enfin une turbomachine, telle qu'un turboréacteur ou un turbopropulseur, comprenant un ensemble rotatif tel que décrit dans la présente demande de brevet.The invention finally relates to a turbomachine, such as a turbojet or a turboprop, comprising a rotary assembly as described in the present patent application.

D'autres avantages et caractéristiques de l'invention apparaîtront à la lecture de la description suivante faite à titre d'exemple non limitatif et en référence aux dessins annexés dans lesquels :

  • la figure 1 est une vue schématique partielle en coupe axiale d'une turbine basse-pression de turbomachine selon l'art antérieur ;
  • la figure 2 est une vue schématique partielle en perspective depuis l'amont de deux aubes adjacentes montées sur un disque de la turbine de la figure 1 ;
  • la figure 3 est une vue schématique en coupe axiale d'un ensemble rotatif selon un premier mode de réalisation l'invention ;
  • la figure 4 est une vue en perspective de l'ensemble rotatif de la figure 3 ;
  • la figure 5 est une vue schématique en coupe axiale d'un ensemble rotatif selon un deuxième mode de réalisation, n'appartenant pas à l'invention ;
  • la figure 6 est une vue schématique en coupe axiale d'un ensemble rotatif selon un troisième mode de réalisation de l'invention.
Other advantages and characteristics of the invention will appear on reading the following description given by way of non-limiting example and with reference to the appended drawings in which:
  • the figure 1 is a partial schematic view in axial section of a turbomachine low-pressure turbine according to the prior art;
  • the picture 2 is a partial schematic perspective view from upstream of two adjacent blades mounted on a turbine disk of the figure 1 ;
  • the picture 3 is a schematic view in axial section of a rotary assembly according to a first embodiment of the invention;
  • the figure 4 is a perspective view of the rotary assembly of the picture 3 ;
  • the figure 5 is a schematic view in axial section of a rotary assembly according to a second embodiment, not belonging to the invention;
  • the figure 6 is a schematic view in axial section of a rotary assembly according to a third embodiment of the invention.

On se réfère tout d'abord à la figure 1 qui représente une turbine basse pression 10 selon la technique antérieure, agencée en aval d'une turbine haute pression 12, et à la figure 2 qui représente plus en particulier deux aubes 14 montées sur un disque rotatif 16 de cette turbine 10. La turbine basse pression 10 comprend une alternance axiale d'étages de rangées annulaires d'aubes fixes 18, appelées distributeurs, et d'étage de disques rotatifs 16 comportant à leurs périphéries une pluralité d'aubes 14, ces étages étant agencés autour d'un axe X de la turbomachine.We first refer to the figure 1 which represents a low pressure turbine 10 according to the prior art, arranged downstream of a high pressure turbine 12, and at the figure 2 which more particularly represents two vanes 14 mounted on a rotating disc 16 of this turbine 10. The low pressure turbine 10 comprises an axial alternation of stages of annular rows of fixed vanes 18, called distributors, and stages of rotating discs 16 comprising at their peripheries a plurality of vanes 14, these stages being arranged around an axis X of the turbomachine.

Dans le présent mémoire, tout comme dans le domaine technique concerné, les termes amont AM et aval AV sont définis de sorte que l'amont se trouve axialement du côté d'où provient le flux d'écoulement général de la turbomachine, et l'aval se trouve axialement du côté vers lequel s'écoule ce même flux.In this memorandum, as in the technical field concerned, the terms upstream AM and downstream AV are defined so that the upstream is axially on the side from which the general flow of the turbomachine originates, and the downstream is located axially on the side towards which this same flow flows.

Chaque disque 16 comprend à sa périphérie externe des dents (dont le sommet est référencé 20) disposées en alternance avec des alvéoles (dont le fond est référencé 22) dans lesquelles sont engagés axialement et retenus radialement des pieds d'aubes (dont l'extrémité interne est référencée 24), ces aubes 14 s'étendant radialement depuis les alvéoles 22 dans une veine annulaire d'écoulement 26 d'un flux de gaz chaud issu d'une chambre de combustion amont (non représenté).Each disc 16 comprises at its outer periphery teeth (whose top is referenced 20) arranged alternately with cells (whose bottom is referenced 22) in which are axially engaged and radially retained blade roots (whose end internal is referenced 24), these blades 14 extending radially from the cells 22 in an annular flow path 26 of a flow of hot gas from an upstream combustion chamber (not shown).

Plus particulièrement, chaque aube comprend radialement depuis l'extérieur vers l'intérieur une pale 28, une plate-forme 30 s'étendant sensiblement perpendiculairement par rapport à l'axe d'allongement de l'aube 14, et une échasse 32 reliant la plate-forme au pied d'aube 24. Les pieds d'aube 24 ont une forme par exemple en queue d'aronde ou analogue pour assurer leur retenue radiale dans les alvéoles 22. Les plates-formes 30 des aubes sont agencées circonférentiellement bout à bout de manière à définir ensemble la limite interne idéale du flux d'écoulement des gaz chauds circulant dans la turbine. Selon cette disposition, des espaces sont formés entre deux échasses 32 circonférentiellement adjacentes, dans la zone annulaire s'étendant radialement depuis les plates-formes 30 jusqu'au disque 16, et sont appelés des cavités inter-échasses ou inter-aubes 34. Des cavités dites de fond d'alvéole 36 sont également formées par des espaces radiaux séparant les pieds d'aubes 24 des fonds 22 des alvéoles. Des parois 38, 40 s'étendent radialement vers l'intérieur depuis l'amont et l'aval des plates-formes jusqu'aux pieds 24 des aubes et forment des moyens d'étanchéité axiale de la zone annulaire s'étendant radialement depuis les plates-formes 30 jusqu'au disque 16, et donc des cavités inter-aubes 34, en assurant leur obturation.More particularly, each blade comprises radially from the outside inwards a blade 28, a platform 30 extending substantially perpendicularly with respect to the axis of elongation of the blade 14, and a stilt 32 connecting the platform at the blade root 24. The blade roots 24 have a shape, for example dovetail or the like, to ensure their radial retention in the cells 22. The platforms 30 of the blades are arranged circumferentially end to end. tip so as to define together the ideal internal limit of the flow rate of the hot gases circulating in the turbine. According to this arrangement, spaces are formed between two circumferentially adjacent stilts 32, in the annular zone extending radially from the platforms 30 to the disc 16, and are called inter-stilt or inter-blade cavities 34. So-called cell bottom cavities 36 are also formed by radial spaces separating the blade roots 24 funds 22 of the cells. Walls 38, 40 extend radially inwards from upstream and downstream of the platforms as far as the roots 24 of the blades and form axial sealing means for the annular zone extending radially from the platforms 30 up to disc 16, and therefore inter-blade cavities 34, ensuring their closure.

Cette étanchéité axiale des cavités inter-aubes 34 est importante, car si une partie des gaz de veine circule à travers ces cavités, elle ne participe pas à l'entrainement en rotation des aubes 14 et chauffe directement les dents 20 du disque formant le fond des cavités inter-aubes 34, ce qui conduit à une augmentation de la température des disques 16 pouvant les endommager et réduire leur durée de vie.This axial sealing of the inter-blade cavities 34 is important, because if part of the stream gas circulates through these cavities, it does not participate in the rotational drive of the blades 14 and directly heats the teeth 20 of the disc forming the bottom. inter-blade cavities 34, which leads to an increase in the temperature of the discs 16 which can damage them and reduce their service life.

La paroi radiale amont 38 de la plate-forme est reliée à un becquet 42 s'étendant vers l'amont et la paroi radiale aval 40 est reliée à un becquet 44 s'étendant vers l'aval. Les becquets 42, 44 s'étendent axialement entre les étages consécutifs de la turbine afin de conserver en partie l'intégrité structurelle de la veine 26 entre chaque étage de turbine, ce qui limite la circulation de gaz chauds radialement vers l'intérieur de la turbine.The upstream radial wall 38 of the platform is connected to a spoiler 42 extending upstream and the radial downstream wall 40 is connected to a spoiler 44 extending downstream. The spoilers 42, 44 extend axially between consecutive stages of the turbine in order to partially preserve the structural integrity of the stream 26 between each stage of the turbine, which limits the circulation of hot gases radially inward of the turbine.

Les disques sont fixés les uns aux autres par boulonnage, en 46, de brides annulaires 48, 50 s'étendant axialement les unes en direction des autres depuis chaque disque. Un anneau labyrinthe 52 est également positionné axialement entre chaque couple de disques 16 adjacents et comprend des bras annulaires amont et aval 54, 56 s'étendant axialement jusqu'à ces disques. Les brides de fixation 48, 50 entre les disques sont ainsi protégées des gaz de veine par les bras 54, 56 de l'anneau labyrinthe 52. L'anneau labyrinthe 52 comprend en outre une paroi annulaire radiale interne 58 de fixation au boulonnage 46 des brides 48, 50 des disques, et coopère par des léchettes 60 annulaires externes avec les extrémités internes des aubes 18 des distributeurs, afin de limiter la circulation des gaz de veine intérieurement par rapport à ces aubes 18.The discs are fixed to each other by bolting, at 46, annular flanges 48, 50 extending axially towards each other from each disc. A labyrinth ring 52 is also positioned axially between each pair of adjacent discs 16 and comprises upstream and downstream annular arms 54, 56 extending axially as far as these discs. The fixing flanges 48, 50 between the discs are thus protected from the stream gases by the arms 54, 56 of the labyrinth ring 52. The labyrinth ring 52 also comprises an internal radial annular wall 58 for fixing to the bolting 46 of the flanges 48, 50 of the discs, and cooperates via external annular wipers 60 with the ends inside the vanes 18 of the distributors, in order to limit the flow of stream gases internally with respect to these vanes 18.

Afin d'assurer le bon fonctionnement de la turbomachine, un air de refroidissement A est prélevé, dans un compresseur basse-pression ou haute-pression par exemple, et acheminé vers la partie interne de la turbine jusqu'aux cavités de fond d'alvéole 36 afin d'assurer le refroidissement du disque 16 et de protéger ce dernier de l'échauffement provoqué par les gaz chauds du flux de veine 26. Afin d'autoriser la circulation de l'air de refroidissement A en aval des cavités 36 de fond d'alvéole, ces dernières débouchent en aval intérieurement par rapport au bras 54 de l'anneau labyrinthe 52 en appui axial sur le disque 16. Cette configuration permet à l'air de refroidissement A de circuler plus en aval radialement entre l'anneau labyrinthe 52 et les brides 48, 50 de fixation entre les disques 16, afin d'en assurer également le refroidissement.In order to ensure the proper functioning of the turbine engine, cooling air A is taken, from a low-pressure or high-pressure compressor for example, and routed to the internal part of the turbine as far as the cell bottom cavities. 36 in order to ensure the cooling of the disk 16 and to protect the latter from the heating caused by the hot gases of the stream flow 26. In order to allow the circulation of the cooling air A downstream of the cavities 36 of bottom of cell, the latter open downstream internally with respect to the arm 54 of the labyrinth ring 52 in axial support on the disc 16. This configuration allows the cooling air A to circulate further downstream radially between the labyrinth ring 52 and the flanges 48, 50 for fixing between the discs 16, in order to also ensure the cooling thereof.

En fonctionnement, les gaz chauds circulant dans la veine 26 peuvent circuler à travers des interstices 62 formés entre les bords en vis-à-vis circonférentiel des parois radiales amont et aval 38, 40 reliées aux plates-formes 30 et recouvrant axialement les cavités inter-aubes 34. Le nombre d'interstices 62 est relativement élevé puisqu'il dépend directement du nombre de plates-formes 30 formant la limite interne de la veine, ce qui induit une fuite totale non négligeable à travers les cavités inter-aubes, qui nuit aux performances de la turbine. Par ailleurs, la géométrie de l'assemblage formé par ces parois radiales 38, 40 et les plates-formes 30 n'autorise pas à réaliser les aubes en Composite à Matrice Céramique (C.M.C.), car cela générerait notamment des problèmes de flexion des fibres du matériau lors de la fabrication. Les récents développements conduisent en effet à utiliser des aubes réalisées en matériau C.M.C. L'utilisation de ce type de matériau permet de réduire le poids des aubes et d'augmenter leur résistance aux températures élevées.In operation, the hot gases circulating in the stream 26 can circulate through the interstices 62 formed between the circumferential facing edges of the upstream and downstream radial walls 38, 40 connected to the platforms 30 and axially covering the internal cavities. -blades 34. The number of interstices 62 is relatively high since it directly depends on the number of platforms 30 forming the internal limit of the stream, which induces a non-negligible total leak through the inter-blade cavities, which impairs turbine performance. Furthermore, the geometry of the assembly formed by these radial walls 38, 40 and the platforms 30 does not allow the blades to be made of Ceramic Matrix Composite (C.M.C.), because this would in particular generate problems of fiber bending. material during manufacture. Recent developments lead to the use of blades made of C.M.C. The use of this type of material makes it possible to reduce the weight of the blades and to increase their resistance to high temperatures.

Afin de pouvoir réaliser les aubes 14 en C.M.C, ou de limiter les fuites au sein des cavités inter-aubes 34, il est donc nécessaire de concevoir de nouveaux moyens d'étanchéité axiale de la zone annulaire s'étendant radialement depuis les plates-formes 30 jusqu'au disque 16, ces moyens d'étanchéité ne devant pas générer un poids trop important supporté par les plates-formes en rotation, du aux effets centrifuges.In order to be able to produce the blades 14 in CMC, or to limit the leaks within the inter-blade cavities 34, it is therefore necessary to designing new axial sealing means for the annular zone extending radially from the platforms 30 to the disc 16, these sealing means not having to generate too great a weight supported by the rotating platforms, due to centrifugal effects.

Il est ainsi conseillé d'utiliser des moyens d'étanchéité pouvant s'agencer à l'amont et/ou plus avantageusement à l'aval de cette zone, et se présentant en deux parties annulaires structurellement distinctes l'une de l'autre, l'une interne 64 et l'autre externe 66. En outre, seule la partie externe 66 des moyens d'étanchéité est retenue par les plates-formes 30 en rotation. Ainsi, la charge supportée par les plates-formes 30 est diminuée. De plus, il est proposé de former ces deux parties de manière que leurs extrémités radiales en vis-à-vis puissent se déplacer radialement l'une par rapport à l'autre, afin que les dilatations relatives entre l'aube 14 et ces moyens d'étanchéité 64, 66 ne résultent qu'en un déplacement relatif entre ces deux parties, et non en apparition de contraintes sur les plates-formes 30 ou de jeux radiaux. Afin de ne pas autoriser de fuites entre ces deux parties, leurs extrémités radiales sont en outres formées de manière à glisser l'une sur l'autre de façon étanche.It is thus advisable to use sealing means which can be arranged upstream and/or more advantageously downstream of this zone, and being presented in two annular parts structurally distinct from each other, one internal 64 and the other external 66. In addition, only the external part 66 of the sealing means is retained by the platforms 30 in rotation. Thus, the load supported by the platforms 30 is reduced. In addition, it is proposed to form these two parts so that their facing radial ends can move radially with respect to each other, so that the relative expansions between the blade 14 and these means sealing 64, 66 only result in a relative movement between these two parts, and not in the appearance of stresses on the platforms 30 or radial clearances. In order not to allow leaks between these two parts, their radial ends are also formed so as to slide one over the other in a sealed manner.

La solution proposée, d'après les caractéristiques principales évoquées ci-dessus, peut se décliner structurellement selon trois exemples non limitatifs représentés le premier aux figures 3 et 4, le deuxième à la figure 5, et le troisième à la figure 6.The solution proposed, according to the main characteristics mentioned above, can be broken down structurally according to three non-limiting examples represented the first in figures 3 and 4 , the second to figure 5 , and the third to the figure 6 .

Dans le premier exemple représenté aux figures 3 et 4, on forme les moyens d'étanchéité à l'aval de la zone annulaire s'étendant radialement depuis les plates-formes 30 jusqu'au disque 16, et comprenant les cavités inter-aubes 34. De manière équivalente et symétrique, il est possible de placer ces moyens d'étanchéité à l'amont de cette zone.In the first example shown in figures 3 and 4 , the sealing means are formed downstream of the annular zone extending radially from the platforms 30 to the disk 16, and comprising the inter-blade cavities 34. Equivalently and symmetrically, it is possible to place these sealing means upstream of this zone.

Ainsi, selon l'exemple décrit aux figures 3 et 4, les plates-formes 30 sont reliées à leurs extrémités amont à des parois 38 s'étendant radialement jusqu'aux dents 20 des disques, et comprenant chacun au voisinage de leurs extrémités internes des becquets 42 s'étendant vers l'amont. Les plates-formes 30 sont en outre chacune reliées à leurs extrémités aval à un becquet 44 s'étendant vers l'aval.Thus, according to the example described in figures 3 and 4 , the platforms 30 are connected at their upstream ends to walls 38 extending radially as far as the teeth 20 of the discs, and each comprising in the vicinity of their internal ends spoilers 42 extending towards upstream. The platforms 30 are also each connected at their downstream ends to a spoiler 44 extending downstream.

La partie interne 64 des moyens d'étanchéité est formée d'un anneau, c'est-à-dire d'une pièce s'étendant annulairement, de préférence fendu, mais qui peut également être formé de plusieurs secteurs agencés circonférentiellement bout à bout. Cet anneau interne 64 s'étend radialement de l'intérieur vers l'extérieur depuis une zone du disque située entre les alvéoles 22 et les brides 48 du disque 16 jusqu'à approximativement le milieu des échasses 32. Il comprend une paroi radiale principale 67 qui est maintenue en appui contre les extrémités aval des échasses 32 et des dents 20 du disque par un bras annulaire amont 54 d'un anneau labyrinthe aval.The internal part 64 of the sealing means is formed of a ring, that is to say of a piece extending annularly, preferably split, but which can also be formed of several sectors arranged circumferentially end to end. . This internal ring 64 extends radially from the inside outwards from a zone of the disc located between the cells 22 and the flanges 48 of the disc 16 up to approximately the middle of the stilts 32. It comprises a main radial wall 67 which is held against the downstream ends of the stilts 32 and the teeth 20 of the disc by an upstream annular arm 54 of a downstream labyrinth ring.

L'anneau interne 64 comprend en outre à son extrémité interne une partie annulaire en crochet 68 engagée sur le disque 16, et destinée à bloquer radialement l'anneau 64. Cette partie en crochet 68, reliée à l'extrémité interne de la paroi radiale principale 67, commence à s'étendre radialement de l'extérieur vers l'extérieur au niveau des dents 20 du disque, juste à l'intérieur de la zone d'appui du bras annulaire 54 de l'anneau labyrinthe, et à l'intérieur des zones d'appui entre les dents 20 du disque et les pieds d'aubes 24 en fonctionnement. Elle comprend une paroi annulaire 70 écartée axialement du disque 16 et s'étendant vers l'intérieur, et reliée à son extrémité interne à un rebord 72 annulaire orienté vers l'amont. Ce rebord 72 s'engage avec des portions en saillie 74 formées de manière discontinue circonférentiellement sur la face aval du disque 16, radialement entre les dents 20 du disque et les brides 48, et qui comprennent chacune une paroi cylindrique interne d'appui du rebord 72 de la partie en crochet 68.The inner ring 64 further comprises at its inner end an annular hook part 68 engaged on the disk 16, and intended to block the ring 64 radially. This hook part 68, connected to the inner end of the radial wall main 67, begins to extend radially from the outside outward at the level of the teeth 20 of the disc, just inside the bearing zone of the annular arm 54 of the labyrinth ring, and at the inside the bearing areas between the teeth 20 of the disc and the blade roots 24 in operation. It comprises an annular wall 70 spaced axially from the disc 16 and extending inwards, and connected at its inner end to an annular rim 72 facing upstream. This flange 72 engages with projecting portions 74 formed discontinuously circumferentially on the downstream face of the disc 16, radially between the teeth 20 of the disc and the flanges 48, and which each comprise an internal cylindrical wall supporting the flange. 72 of the crochet part 68.

L'air de refroidissement A provenant des cavités de fond d'alvéole peut s'échapper vers l'aval dans l'espace annulaire axial laissé entre le disque 16 et la partie en crochet 68, et circuler vers l'intérieur entre les portions en saillie 74 du disque, entre le rebord 72 de la partie en crochet et le disque, pour enfin longer axialement la bride aval 48 du disque.The cooling air A coming from the cell bottom cavities can escape downstream in the axial annular space left between the disc 16 and the hook part 68, and circulate inwards between the projecting portions 74 of the disc, between the flange 72 of the hooked part and the disc, to finally follow axially the downstream flange 48 of the disc.

La partie interne 64 des moyens d'étanchéité comprend à son extrémité externe un rebord 76 annulaire en décrochement vers l'aval par rapport à la paroi radiale principale 67. Ce rebord est destiné à venir en appui axial vers l'amont contre la partie externe 66 des moyens d'étanchéité pour en assurer le maintien axial contre les aubes 14.The internal part 64 of the sealing means comprises at its external end an annular flange 76 offset downstream with respect to the main radial wall 67. This flange is intended to come into axial abutment upstream against the external part 66 sealing means to ensure the axial retention against the blades 14.

La partie externe 66 des moyens d'étanchéité est formée d'un anneau, c'est-à-dire d'une pièce s'étendant annulairement, de préférence formé de six à huit secteurs agencés circonférentiellement bout à bout, mais qui peut également être fendu. Cet anneau externe 66 s'étend radialement depuis les plates-formes 30 jusqu'au rebord externe en décrochement 76 de la partie interne des moyens d'étanchéité. Il comprend une paroi tronconique 78 principale s'étendant vers l'intérieur et vers l'aval depuis une extrémité externe engagée dans une gorge 80 radiale formée sur les faces internes des plates-formes 30. La paroi tronconique 78 est de plus reliée à son extrémité interne à un rebord annulaire 82 orienté vers l'amont. Un joint annulaire 84 est agencé axialement entre les extrémités aval des échasses 32, et la partie interne de la paroi tronconique 78. Le joint 84 est retenu radialement par le rebord interne 82 de la paroi tronconique.The outer part 66 of the sealing means is formed of a ring, that is to say of a part extending annularly, preferably formed of six to eight sectors arranged circumferentially end to end, but which can also be split. This outer ring 66 extends radially from the platforms 30 to the recessed outer edge 76 of the inner part of the sealing means. It comprises a main frustoconical wall 78 extending inwards and downstream from an outer end engaged in a radial groove 80 formed on the internal faces of the platforms 30. The frustoconical wall 78 is further connected to its inner end to an annular rim 82 facing upstream. An annular seal 84 is arranged axially between the downstream ends of the stilts 32, and the internal part of the frustoconical wall 78. The seal 84 is retained radially by the internal rim 82 of the frustoconical wall.

L'extrémité interne de la paroi tronconique 78 est agencée en contact sur la face amont du rebord externe en décrochement 76 de la partie interne 64 des moyens d'étanchéité. En fonctionnement, le joint annulaire 84 s'étend circonférentiellement et repousse la paroi tronconique 78 vers l'aval, ce qui permet de contraindre axialement l'extrémité interne de la paroi tronconique 78 contre le rebord en décrochement 76 de la partie interne, de manière à rendre étanche l'interface entre la partie interne 64 et la partie externe 66 des moyens d'étanchéité. De plus, le rebord en décrochement 76 de la partie interne présente une dimension radiale suffisante pour permettre à l'extrémité interne de la paroi tronconique 78 de glisser radialement le long de sa surface amont, tout en conservant l'étanchéité entre les deux parties.The internal end of the frustoconical wall 78 is arranged in contact on the upstream face of the external rim 76 offset from the internal part 64 of the sealing means. In operation, the annular seal 84 extends circumferentially and pushes the frustoconical wall 78 downstream, which makes it possible to axially constrain the internal end of the frustoconical wall 78 against the recessed rim 76 of the internal part, so as to to seal the interface between the internal part 64 and the external part 66 of the sealing means. In addition, the recessed edge 76 of the internal part has a sufficient radial dimension to allow the internal end of the frustoconical wall 78 to slide radially along its upstream surface, while maintaining the seal between the two parts.

Comme il ressort de cette réalisation, seule la partie externe 66 des moyens d'étanchéité est supportée en rotation par les plates-formes 30, par son appui dans la gorge 80 des faces internes des plates-formes. La partie interne 64 est quant à elle retenue exclusivement dans cette solution par le disque 16 grâce à la partie en crochet 68 engagée sur les portions en saillie 74.As emerges from this embodiment, only the external part 66 of the sealing means is supported in rotation by the platforms 30, by its support in the groove 80 of the internal faces of the platforms. The internal part 64 is retained exclusively in this solution by the disc 16 thanks to the hooked part 68 engaged on the projecting portions 74.

Dans l'exemple représenté à la figure 5, la réalisation diffère de l'exemple représenté aux figures 3 et 4 seulement en ce que la paroi radiale 67 de la partie interne 64 des moyens d'étanchéité est reliée à son extrémité externe à deux branches radiales 86, 88 annulaires écartées axialement, de manière similaire à une fourchette, et en ce que la partie externe 66 des moyens d'étanchéité comprend une paroi radiale 90 annulaire s'étendant depuis son extrémité externe, et s'engageant axialement entre les deux branches radiales 86, 88.In the example shown in figure 5 , the construction differs from the example shown in figures 3 and 4 only in that the radial wall 67 of the internal part 64 of the sealing means is connected at its external end to two radial branches 86, 88 spaced apart axially, similarly to a fork, and in that the external part 66 sealing means comprises an annular radial wall 90 extending from its outer end, and engaging axially between the two radial branches 86, 88.

En fonctionnement, la différence de pression entre les cavités inter-aubes 34 et la zone aval des moyens d'étanchéité induit une rotation vers l'aval des extrémités en vis-à-vis des parties interne 64 et externe 66 des moyens d'étanchéité, ce qui entraine une mise en contact de la paroi radiale 90 de la partie externe contre l'une des branches 86, 88 de la partie interne, afin d'assurer l'étanchéité. Comme pour le premier exemple, un glissement entre les deux parties est autorisé par la dimension radiale des branches, tout en conservant l'étanchéité.In operation, the pressure difference between the inter-blade cavities 34 and the zone downstream of the sealing means induces a downstream rotation of the ends facing the internal 64 and external 66 parts of the sealing means. , which brings the radial wall 90 of the outer part into contact against one of the branches 86, 88 of the inner part, in order to ensure sealing. As for the first example, a sliding between the two parts is authorized by the radial dimension of the branches, while retaining the seal.

Dans le dernier exemple de réalisation représenté à la figure 6, la réalisation diffère de l'exemple représenté aux figures 3 et 4 seulement en ce que les portions en saillie 74' sont formées non pas radialement entre les alvéoles 22 et les brides 48, mais sur les dents 20 du disque, extérieurement aux cavités de fond d'alvéole 36. La paroi principale 67' de la partie interne 64' des moyens d'étanchéité est raccourcie radialement afin que la partie annulaire en crochet 68' s'engage par son rebord interne 72' sur ces portions en saillie 74'. Le bras annulaire 54 de l'anneau labyrinthe aval est en appui non plus sur la paroi principale 67, mais sur la paroi annulaire 70' de la partie en crochet 68'. Il est à noter qu'un contact axial est assuré entre le rebord interne 72' de la partie en crochet et l'alternance circonférentielle des dents 20 du disque et des pieds d'aubes 24, et ceci radialement au niveau des zones d'appui entre les dents 20 du disque et les pieds d'aubes 24 en fonctionnement, afin d'assurer l'étanchéité entre les cavités de fond d'alvéole 36 et les cavités inter-aube 34.In the last exemplary embodiment shown in figure 6 , the construction differs from the example shown in figures 3 and 4 only in that the projecting portions 74' are formed not radially between the cells 22 and the flanges 48, but on the teeth 20 of the disc, externally to the cell bottom cavities 36. The main wall 67' of the part 64' of the sealing means is shortened radially so that the annular hook part 68' engages via its internal edge 72' on these projecting portions 74'. The annular arm 54 of the downstream labyrinth ring no longer rests on the main wall 67, but on the annular wall 70' of the hook part 68'. It should be noted that an axial contact is ensured between the internal rim 72' of the hooked part and the circumferential alternation of the teeth 20 of the disc and of the blade roots 24, and this radially at the level of the support zones. between the teeth 20 of the disc and the blade roots 24 in operation, in order to ensure sealing between the cell bottom cavities 36 and the inter-blade cavities 34.

Par rapport aux autres exemples décrits, cette solution permet de réduire les contraintes exercées sur la partie interne des moyens d'étanchéité, car sa taille plus réduite permet d'éviter l'apparition de gradients thermiques importants. En revanche, la localisation des portions en saillie 74' sur les dents 20 du disque implique une concentration de contraintes mécaniques plus élevées au niveau des parties internes des dents 20 du disque rattachées au disque, ces portions en saillie 74' servant à la retenue de la partie interne des moyens d'étanchéité en fonctionnement.Compared to the other examples described, this solution makes it possible to reduce the stresses exerted on the internal part of the sealing means, since its smaller size makes it possible to avoid the appearance of significant thermal gradients. On the other hand, the location of the protruding portions 74' on the teeth 20 of the disc implies a concentration of higher mechanical stresses at the level of the internal parts of the teeth 20 of the disc attached to the disc, these protruding portions 74' serving to retain the the internal part of the sealing means in operation.

Claims (12)

  1. A rotary assembly for a turbomachine, comprising:
    - a disc (16) having an external periphery having an alternation of slots (22) and teeth (20),
    - blades (14) extending radially from the disc (16), and roots (24) of which are engaged axially and held radially in the slots (22) of the disc, the blades having an upstream side and a downstream side,
    - platforms (30) extending circumferentially from the blades (14) and which are arranged circumferentially end to end, opposite each other,
    - axial sealing means for at least one of an upstream and downstream sealing of an annular zone extending radially between the platforms (30) and the disc (16),
    characterised in that said sealing means comprise radially an internal annular part (64) and an external annular part (66) structurally separate from each other, the external part (66) of the sealing means comprising a frustoconical wall (78) extending inwards from its external end, and the internal part (64) of the sealing means comprising at its external end an annular rim (76) having a step and which is in axial abutment against the internal end of the frustoconical wall (78), which can slide radially along the stepped rim (76) of the internal part (64), an annular seal (84) being interposed axially between the axial ends of the blades (14) and the frustoconical wall (78) of the external part, the internal end of the frustoconical wall (78) being arranged in contact with the upstream face of the external stepped rim (76) of the internal wall (64), so that the annular seal (84) can push the frustoconical wall (78) downstream, which makes it possible to axially force the internal end of the frustoconical wall (78) against the stepped rim (76) of the internal part (64).
  2. A rotary assembly according to claim 1, characterised in that the facing radial ends of the internal annular part (64) and of the external annular part (66) are adapted for a relative radial movements by sliding sealingly, only an absorption of the centrifugal forces of the external part being provided in rotation by the platforms (30).
  3. A rotary assembly according to claim 1 or 2, characterised in that the internal annular part (64) and the external annular part (66) of the sealing means comprise respectively two rings held axially and radially opposite the annular zone extending radially between the platforms (30) and the disc (16).
  4. A rotary assembly according to one of claims 1 to 3, characterised in that air circulation means are formed on the disc (16) and/or the internal part (64) of the sealing means, and configured so as to allow air (A) to circulate between the upstream side and/or downstream side of the rotary assembly and the slots (22).
  5. A rotary assembly according to one of the preceding claims, characterised in that the external part (66) of the sealing means comprises an external end engaged in a radial annular groove (80) formed on the internal faces of the platforms (30), and in that the internal part (64) of the sealing means provides axial locking of the external part (66) against the annular zone extending radially from the platforms (30) as far as the disc (16).
  6. A rotary assembly according to one of the preceding claims, characterised in that the internal part (64) of the sealing means is held radially by the disc.
  7. A rotary assembly according to one of the preceding claims, characterised in that:
    - it comprises a sealing ring (52) comprising an annular arm (54) and annular sealing lips (60) intended to cooperate sealingly with an external stator element, and
    - the internal part (64) of the sealing means is held axially against the disc (16) and the blades (14) by said annular arm (54).
  8. A rotary assembly according to one of the preceding claims, characterised in that
    - the internal part (64) of the sealing means comprises an annular hook part (68) engaged with at least one rim of one of the faces of the disc for a radial relative locking,
    - and the rims of the disc are formed by internal faces of a plurality of projecting portions (74) situated on one of the faces of the disc internally with respect to the bottoms of the slots (22) of the disc, and following each other circumferentially discontinuously, the annular hook part (68) of the internal part (64) of the sealing means extending radially from the zone situated radially between:
    ∘ the locations where the teeth (20) of the disc bear against the blade roots (24) in operation, and
    ∘ the bottoms of the slots (22),
    as far as the internal faces of the projecting portions (74), the annular hook part (68) furthermore not being in axial abutment against the disc (16) at least locally so as to enable air (A) to circulate between the upstream and/or downstream side of the rotary assembly and the slots (22).
  9. A rotary assembly according to one of claims 1 to 7, characterised in that
    - the internal part (64) of the sealing means comprises an annular hook part (68) engaged with at least one rim of one of the faces of the disc for radial relative locking,
    - and the rims of the disc are formed by internal faces of a plurality of projecting portions (74) situated on the external parts of the radial faces of the teeth (20) of the disc, and follow each other circumferentially discontinuously, the internal end of the annular hook part (68) engaged on these internal faces being furthermore in axial contact with the teeth (20) of the disc and the blade roots (24) at the locations where the teeth (20) of the disc bear against the blade roots (24) in operation.
  10. A rotary assembly according to one of the preceding claims, characterised in that the blades (14) comprise a ceramic matrix composite.
  11. A turbomachine turbine, characterised in that it comprises a rotary assembly according to one of the preceding claims.
  12. A turbomachine, such as a turbojet engine or turboprop engine, characterised in that it comprises a rotary assembly according to one of claims 1 to 10.
EP14790197.9A 2013-09-25 2014-09-23 Rotary assembly for turbomachine Active EP3049637B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR1359237A FR3011031B1 (en) 2013-09-25 2013-09-25 ROTARY ASSEMBLY FOR TURBOMACHINE
PCT/FR2014/052376 WO2015044579A1 (en) 2013-09-25 2014-09-23 Rotary assembly for a turbomachine

Publications (2)

Publication Number Publication Date
EP3049637A1 EP3049637A1 (en) 2016-08-03
EP3049637B1 true EP3049637B1 (en) 2023-01-25

Family

ID=50424336

Family Applications (1)

Application Number Title Priority Date Filing Date
EP14790197.9A Active EP3049637B1 (en) 2013-09-25 2014-09-23 Rotary assembly for turbomachine

Country Status (4)

Country Link
US (1) US10267172B2 (en)
EP (1) EP3049637B1 (en)
FR (1) FR3011031B1 (en)
WO (1) WO2015044579A1 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3022944B1 (en) * 2014-06-26 2020-02-14 Safran Aircraft Engines ROTARY ASSEMBLY FOR TURBOMACHINE
FR3039589B1 (en) * 2015-07-28 2020-01-10 Safran Aircraft Engines TURBOMACHINE STAGE, PARTICULARLY LOW-PRESSURE TURBINE
FR3085420B1 (en) 2018-09-04 2020-11-13 Safran Aircraft Engines ROTOR DISC WITH BLADE AXIAL STOP, SET OF DISC AND RING AND TURBOMACHINE
FR3092609B1 (en) * 2019-02-12 2021-02-12 Safran Aircraft Engines TURBINE ASSEMBLY FOR AIRCRAFT TURBOMACHINE WITH IMPROVED DISC COOLING CIRCUIT
FR3092865B1 (en) * 2019-02-19 2021-01-29 Safran Aircraft Engines ROTOR DISK WITH BLADE AXIAL STOP, DISC AND RING SET AND TURBOMACHINE
FR3112366B1 (en) * 2020-07-10 2022-07-22 Safran Aircraft Engines Wedge for retaining a turbomachine retaining ring
FR3127255A1 (en) 2021-09-23 2023-03-24 Safran Aircraft Engines Rotary assembly for turbomachine
US11686202B1 (en) * 2021-12-20 2023-06-27 Rolls-Royce North American Technologies Inc. Rotor damper with contact biasing feature for turbine engines

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US4192633A (en) * 1977-12-28 1980-03-11 General Electric Company Counterweighted blade damper
GB8705216D0 (en) * 1987-03-06 1987-04-08 Rolls Royce Plc Rotor assembly
FR2700807B1 (en) * 1993-01-27 1995-03-03 Snecma Retention and sealing system for blades engaged in axial pinning of a rotor disc.
US6899520B2 (en) * 2003-09-02 2005-05-31 General Electric Company Methods and apparatus to reduce seal rubbing within gas turbine engines
GB0413652D0 (en) * 2004-06-18 2004-07-21 Rolls Royce Plc Gas turbine engine structure
US8251651B2 (en) * 2009-01-28 2012-08-28 United Technologies Corporation Segmented ceramic matrix composite turbine airfoil component
FR2948726B1 (en) * 2009-07-31 2013-07-05 Snecma AUBES WHEEL COMPRISING IMPROVED COOLING MEANS
FR2965291B1 (en) * 2010-09-27 2015-01-23 Snecma UNITARY ASSEMBLY OF ROTOR DISCS FOR A TURBOMACHINE
US8636470B2 (en) * 2010-10-13 2014-01-28 Honeywell International Inc. Turbine blades and turbine rotor assemblies
FR2978793B1 (en) * 2011-08-03 2015-12-04 Snecma ROTOR OF TURBINE FOR A TURBOMACHINE

Also Published As

Publication number Publication date
US10267172B2 (en) 2019-04-23
FR3011031B1 (en) 2017-12-29
US20160222810A1 (en) 2016-08-04
WO2015044579A1 (en) 2015-04-02
FR3011031A1 (en) 2015-03-27
EP3049637A1 (en) 2016-08-03

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